Preliminary maturing of alkalicellulose



April 13,1937, R. BRANDES PRELIMINARY MATURING OF ALKALI CELLULOSE Filed Jan. 7, 1955 MAW mm WM y V t en and thus to cheapen this protracted operar is a l w t fa l radually and indeed to 10 55 physical properties can be obtained when the lation between an adjusted degree of shredd ng 55 Patented Apr. 13, i

V 2.077.164' f rnanmmmmz MATURlgEG or ALKALI- CELLULO Rudolf Brandes, Chemnitz, Germany Application January '1, 1935, Serial No. 802 In Germany January 23, 1934 11' Claims; (Cl. 26010) The invention relates to a process for the acexpressed alkali-cellulose material is put into a celerated preliminary maturing or alkali-cellushredder heated to high temperatures, for ex-' lose. According to the hitherto usual way, the ample 50 C., and first of all-treated for about expressed alkali-cellulose is, for the purpose or -one hour atthis temperature. In this case the 5 preliminary maturing, shredded, put into boxes shredder isadjusted in such a manner that first '5 after being so shredded, and then allowed to mat re i nly a ixi and lo in pr c ss and ture preliminarily for several days in a. room t at s stage a shredding l o y heated to or maintained at a m d rat temperafter the expiration of this period of time there ature. Proposals have not been lacking to shortins h ing proper, and t mp r tion.. Even the complete omission of the presuch an extent that the degree of disinte r tion liminary maturing of alkali-cellulo e ha already increases so that at the conclusion of thevshredbeen frequently mentioned inrliterature, but this n m l mperature is obtained which alprocess, in which, as is known,the alkali-cenulows the xanthation to take place immediately. loseundergoes an increase of dispersivity cannot The maximum Working temperature and v s he 15 usually b dispensed with, It i known t t period of the action of the elevated temperatures expert that,the viscosity of the viscose to be depend of rs "P the character the made depends t high t g' cellulose to be treated. The total duration of liminary maturing of the alkali-cellulose and th t; this working process usually does not exceed four t i upper limbs are placed n th spinning hours but it may be considerably shorter. During 20 vi co its V the working process the shredder is advanta- ,It has been endeavoured to carry out at elegeeusiy p Wel c d for h P p Of P vated temperatures and with reduction of the Venting vaporizatiml of Water and also e storage time to a few hours the preliminary mamg the danger of the efiect 0f turing heretofore carried out at moderate tem- In carrying 9 the P1190955 variationsal'e P 25 peratures and with rather longstoragh Thus sible in several directions. Thus for example there is known f example. a, proposal according the process may be carried out in a single operto which the shredded alkali-cellulose is heated the mixing and loosening Processes at high in a rotating drum at temperatures of 0 temperature and then consecutively the shred- There are however important objects to such a .ding at low temperature bemg efiected for 30 mode of working because there is the possibility ample m F .receptacle' T has the that in that case the further treatment of the vantage of slmphclty reqmres changing of working temperatures or changing tempera- 2323521 2252 gzg gg ggg pm with re ture efiects from outside on the shredder. The

making first: ta rziz szitz rsiesta; 35 the mercerization and preliminary maturing the first part the process at a high processes continuous, endless cellulose strips bemm which remains Constant and then the mg presented treatmentsuch pmcesses are charge is transferred into the second receptacle, 0 accompanied by the disadvantage that they rewhich is not heated or iseven choled, so that the 40 quire an apparatus which difiers. very from. maturing material therein is cooled down to room that ordinarily employed and consequently in very tempera-ma many cases cannot be carried out for this prac- The loosening and shredding may be efiected tical reason. Also these continuous processes both the fir t part f the process and in t have not yet been R out 111 Practice 150 an second part of the process either with a fixed 45 adequate eXtentshredder or adjustably with a gradual change so A r i to the invention the preliminfily that a changing degree of shredding results. The maturing of the alkali-cellulose is eiiected in such temperatures in th tw parts of the process may a manner that it is subjected first to a mixing e dealt with in an analogous manna; p g and loosening process at elevated temperature ably ryin working conditions will be used in 50 and then to a shredding at a temperature that th c nd part of the process. is normal or adu y becomes normal- In order to facilitate regulation of the working Exhaustive experiments have shown that a conditions there may be employed devices thatv good artificial silk, staple fibre etc. with good automatically control or maintain a definite rel desired degree of shredding, i. e.,

can be suited. Theadiustment and an adjusted working temperature} advantageously these devices are also such that the said relationship is adjustable within certain limits so that the peculiarities of the material of the degree of shredding may in this case be carried out in such a manner inter alia that one or both blade shafts of the shredder is or are moved in a direction parallelto itself or themselves until the depth of engagement is obtained.

' The process can in'practice be still further automatized by employing a periodically'reguof the toothed covering lated switch gear for automatically varying the working temperature and/or the depth of engagement of the shredding devices. Then, for ,example by adjusting different marks, contacts, etc., on the time scale of the switch gear, there 2, can be fixed any desired temporal division for the automatic production of the desired alterations 'of' the temperature and of ding the accompanying drawing, which is purely 2 diagrammatic, the application of the invention is shredder A serves for explained by means of two constructional examples.

In Fig. 1 the process according to the invention iscarried out in two shredders A and B. The the carrying out of the first step of the process- (high temperature, low

step has been completed the cover I of the shredder A is raised, the latter is tipped up about the shaft 2,,and the material to be shredded is poured 'outtherein' as the second operation,

narrower interspace between The two shredders shredder B is connected to render it unnecessary in a manner similar to 75 heating over an incline 3 into .the open shredder B. The incline 3 contains a hinged part 3", which can be swung up so as to be out of the way when the shredder B is'tipped up.-

After closing the shredder B there is carried step of the process (low temperature; higher degree of shredding). The higher degree of shredding in the shredder-B is indicated by the the blade-drum 4 and the toothed portion 6. After the completion of this operation the content of the shredder is, by tipping it up, emptied intoa transport vessel 1 over the incline 5.

The hollow peripheral wall of the shredder A is connected to a conduit for supplying a heating medium'and the hollow peripheral wall of the to asupply of cooling water. For the sake of simplicitythe supply and outlet conduits of the heating and media are not shown; if required the connections may be made co-axially to-the shaft 2 in order to remove the connections for the purpose of tipping the shredders.

In Fig. 2 there is shown an apparatus for carrying out the process according-to the invention 1 C. The shredder C is built shredders A.

in a sin le shredder that-of the blade shafts ll are iournalled in bearings II which can be by means of a screw spindle l2 so that by turning the spindle there is produced a change in the. depth of engagement between the-teeth of the blades l2 and of the toothed portion [4.

Through thecover I! of the shredder thereexe;

tends the charging pipe of a parall lator II which is known in'the-case of centraland which is arranged for the 'tions of the pinion the desired of the process. concentrically with the axis of the degree of shred-.

' of electromagnets.

the second been drawn in a very are surrounded by hollow peripheral walls'indicated at 8 and 2 respectively.

, mal temperature and in the reverse direction durof the moved horizontally translation of temperature variations into revolult. 0n the pinion it there of the regulating cord it the 'guide' roller 20 and the is fastened the end which extends over coil drum 2| to the drum 2| is keyed on the shaft 12 so that the temperature variations in the shredder C result in an automatic movement of'the shredder blades IS in relation to the toothed portion l4 and consequently result in a variationof the degree of shredding. The apparatus here represented contains also an arrangement for the automatic control of the temperature inthe shredder C by means of an adjustable central contact switch 23. This contains .a clockwork mechanism by means of which thecontact lever 24 is moved uniformly in a circle and makes for example a complete revolution in the time (for example four hours). provided for theentire carrying-out the lever 24 there are annular contabt pieces 25, 26 over which the lever 24 slides duringits revolution. By means of these contacts electrical circuits are'closed in which there is located besides the battery 21 either the coil 28 or the coil 29 These coils control the cocks 22 and 31 by means of their movable cores. The

cock is located in the conduit 32 of the heating liquid and the cock 3! in-the cooling-water conduit 23. v I

It will be clear from the drawing alone that the apparatus according to-Figure 2 can work quite automatically after the contacts 25, 26 (assumed to be adjustable) have been secured in the correct position and the desired relationship. between the temperature in the shredder and the degree of shredding is also produced by correct placing of the cord l9 on the drum 2|.

The arrangement represented in Fig. 2 for producing automatic controls can hardly be carried out in the construction shown, which has primitive manner, for the purpose of clearness; such arrangements arev however known in complete construction so that the representation may be restricted to a very simple constructional form.

The process according to the invention may be carried out in a particularly simple and practical manner in ordinary shredders for alkali-cellulose. (according to Figure 2, but without possibility of adjustment of a shredding-blade shaft) if the alkali-cellulose is placed in such a shredder and the latter is run in the normal direction during the (second) part of the process proceeding at noring the (first) part of the processproceeding at higher temperature. when, in fact, the toothed shredding blades run in the reverse direction there occurs only a very considerably smaller shredding of the alkalillulose, chiefly only a loosenfelted fibrous mass or a thorough mixing thereof. For the transference to the second part of the process (proceeding at lower temperature) all ,that is necessary is to reverse the direc-- tion'of running of the rotating shredding blades and .to shut off the heating. The above decribed mode of carrying out. the process according to the invention has the advantage that it can be undertaken in any ordinary shredder so that new'apparatus parts are'not necessary. 71

.I claimzr- 1. In a process for the accelerated preliminary maturing of alkali-cellulose, in which the cellulose is alkalized', pressed a shredded, the-steps I of subjecting the alkalized-an pressed cellulose? suspended weight 22. The s to an elevated temperature of about'50 C. for a period of approximately one hour and mixing and loosening the cellulose simultaneously therewith place, and carrying out the shredding operation at a temperature, which is gradually reduced from about 50 C. to'a normal value.

3. In a process for the accelerated preliminary maturing of alkali-cellulose, in which the cellulose is alkalized, pressed and shredded, the steps of subjecting the alkalized and pressed cellulose to an elevated temperature of about 50 C. for a period of approximately one hour and mixing and loosening the cellulose simultaneously-therewith before the shredding of the cellulose takes place,

and carrying out the shredding operation at a temperature, which is gradually reduced from about 50 C. to a normal value, whereby the adjustment of said mechanical treatments to the cellulose and the temperature takes place ,in mutual dependence upon each other.

4. In a process for' the accelerated preliminary maturing of alkali-cellulose, in which the cellulose is alkalized, pressed and shredded, the steps of subjecting the alkalized and pressed cellulose,

to an elevated temperature of about 50 C. for a period of approximately one hour and mixing and loosening the cellulose simultaneously therewith before the shredding of the cellulose takes place, and carrying out the shredding operation at a normal temperature, whereby said treatments to the cellulose are carried out in one and thesame receptacle. 5a

5. In a process for the accelerated prelimi ry maturing of alkali-cellulose, in which the cellulose is alkalized, pressed and shredded, the steps of subjecting the alkalized and pressed cellulose to an-elevated temperature of about 50 C. for a period of approximately one hour and mixing and loosening the cellulose simultaneously therewith before the shredding of the cellulose takes place, and carrying out the shredding operation at a temperature, which is gradually reduced from about 50 C. to a normal value, whereby said treatments to the cellulose are carried out in one and the same receptacle. w

6. In a process-for the accelerated preliminary maturing of alkali-cellulose, inwhich the cellulose is alkalized, pressed and shredded, the steps of subjecting. the alkalized and pressed cellulose to an elevated temperature-of about 50 C. for a period of approximately one hour and mixing and loosening the cellulose simultaneously therewith before the shredding of the cellulose takes place, and carryingout the shredding operation at a normal temperature, whereby said treatments to the cellulose are carried out in one and the same receptacle, which is provided with blades adapted to be rotated in a normal direction and a direction reversed thereto and having a shredding effeet in the normal direction only, by causingthe blades first to rotate for a period of approximately one hour in the reversed direction to mix and loosen the cellulose material and the blades to rotate in the normal direction to shred the same material.

7. In a process for'the' accelerated preliminary maturing of alkali-cellulose, in which the cellulose is alkalized, pressed and shredded, the steps of subjecting the alkalized and pressed cellulose to an elevated temperature of about 50 C. for a period of approximately one hour and mixing and loosening the cellulose simultaneoosly therewith before the shredding of the cellulose takes place, and carrying out the shredding operation at a temperature, which is gradually reduced from about 50 C. to a normal value, whereby said treatments to the cellulose are carried out in one and the same receptacle, which is provided with blades adapted to be rotated in a normal direction and .a direction reversed thereto and having a shredding effect in the normal direction only, by causing the blades first to rotate for a period oi approximately one, hour in the reversed direction to mix and loosen the cellulose material and then causing the blades to rotate in the normal direction to shred the same material.

8. In a process for the accelerated preliminary maturing of alkali-cellulose, in which the cellulose is alkalized, pressed and shredded, the steps ofsubjecting the alkalized and pressed cellulose to an elevated temperature of about 50? C. for a period of approximately one hour and mixing and loosening the cellulose simultaneously therewith before the shredding of the cellulose takes place,- and carrying out the shredding operation at-a temperature, which is gradually reduced from about 50" C; to a normal value, whereby the ad-,

justment of said mechanical treatments to the celn lulose and the temperature takes place in mutual dependence upon each other and said treatments to the cellulose are carried out in one and the same receptacle, which is provided with blades adapted to be rotated in a normal direction and a direction reversed thereto and having a shredding e'fiect in the normal direction only, by causing theblades first to rotate for a period of approximately one hour in the reversed direction to mix and loosen the cellulose material and then; causing the blades to rotate in the normal direction to shred the same material.

-9. In a process for the accelerated preliminary maturing of alkali-cellulose, in which the cellulose is alkalized, pressed and shredded; the steps of subjecting the alkalized and pressed cellulose to an elevated temperature of about 50 C. for a period of approximately one hour and mixing and loosening the cellulose simultaneously therewith before the shredding of the cellulose takes place,

and carrying out the shredding operation at a normal temperature, whereby said treatments to the cellulose are carried out in one and the same receptacle, which is provided with blades adapted to be rotated and to be adjusted with respect to their distance from a-ledger plate, by adjustingfirst a comparatively large space between the rotating blades and the ledger plate to mix and loosen the cellulose material and then adjusting a small space between said blades and the ledger plate to shred the same material.

10. In a process for the accelerated preliminary maturing of alkali-cellulose, in which the cellulose is alkalized, pressed and shredded, the steps of subjecting the alkalized and pressed cellulose to an elevated temperature-of about 50 C. for a period of approximately one hour and mixing and loosening the cellulose simultaneously therewith before the shredding of he cellulose takes place,

p then causing and carrying out the shredding operation at a 7 temperature, which is graduallyreduced from about 50 C. to a normal value,- wh ereby said treatments to the cellulose are carried out in,one and the same receptacle whichiaprovided with blades adaptedto be rotated and to be adjust? with respect-to their distance irom a iekigerpla, by adjusting first a' comparatively large spacerbetween the rotating blade's and'tlie ledger plate-to mix and loosenthe cellulose material and ftheii l0 adjusting a small space between said blades and the ledger plate to shred the samematerial, ll. In a process ior the accelerated preliminary maturing oi alkali-cellulose, in which thecellulose' is alkalized, pressed and'shredded, thelstepsoi lfi'subjecting the alkalized and pressed cellulose to an elevated temperature 01f about50-'C.-iora period oi approximately one hour and mixing and loosening the cellulose simultaneously therewith before the shredding oi the cellulose takes place. and carrying out the shredding operation at a deinperature, which is gradually reduced from about 50? C. to a normal value-whereby the adjustment of said mechanical treatments to'the cellulose and the'tem'peratm'e takes place in mutual dependence upon each other, and said treatment to thecellulom are carried out in one and the same receptacle; which is provided with blades adapted to be rotated and to be-adiusted with respect to their distance from a ledger plate, by ad-.

lusting first a comparatively large space between therrotating blades and the ledger plate to mix and loosen the cellulosematerial and then adjust- .ing a small space between said blades and the i'ledg'erplate to shred the same material.

'fnononr BRANDES. 

